SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af4b87cf5548c0e29babc3ef65ef708da4a00107bb9e403429997dbf9004a8d0' 
  AND token = 'zH7TTGREtfIMaA6ilJigoAl8DB4hCcJ82cD90IYVhTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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