SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cec7f376a5e773a1dbcfe62f4abdf9ad0e6e56221f192326fb1d2791cbb9c34b' 
  AND token = 'VWrJ5Lm6nQ4QBhjLnhQ3sKnVxoTkgyTrKOTu93mdMLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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