SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5e7112fe523245e4f1043af4b3623b2b220f55ee2756259a330130457ade5c8' 
  AND token = 'cTwxUqTuEOW0vMVuitOcEFeFAk4B16BZ24nVC10Vcrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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