SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14f2fb110e2b094d4c9439148989d835d362037a817e75bcadac3d870b80a3b8' 
  AND token = 'PduJzsGTjDo5cUqMqH0zGwsNiJkPgwGae9Qf9Lav7j8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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