SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6a833979531bf92462b09c896a9d0249880a9e9237a20d7b75729618e4217b5' 
  AND token = 'ugtlgRW7IbPZpExgAKbpr7diWkPoR3faXowRz5fG9ik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}