SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c03ab92cb536c34de0b9058cf394c9ec2b4df714589e133199b26575d977ef37' 
  AND token = 'vmE1CQI1ojDdWSLEIrwU9KRZKU/qlamrTgCTB1zhA8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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