SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53e15d63b2d992b6cf577a559b491473043daab2c6e871d268177a66ded09886' 
  AND token = 'y3pB8XZ7rFvQ/rxdrLo2P9PVilJWEp9abqCfH8rFEHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}