SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1755edc536bec5b00aa6b1eeba0cfe26a656e14f25f0f92248c65cbd9333a4e' 
  AND token = 'J6jlEiQR+qK4PPbO31BCmmT3pf8oaGnWB1vcpHJkvYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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