SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a03d4c342e83ba855f8202b26459be03945d7551c868f8020db6bdcb95dddfd' 
  AND token = '1XxUhsGR4vdF/+X1yIZNQ4Vd51l3EpFEACWMZmZ9oDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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