SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91e2c86e0bfcd9be284d64282e136e01f56a1902a9102a8b8f164e32e7bdedc8' 
  AND token = 'J7spiyXawgnXhBf8BUXM1tmnYOwdBz2+REC7KjCSvIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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