SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb093d551b69ed1b8fe961929c6fde6527a50493405b2404290904dd42875714' 
  AND token = 'z3bVYUY3VFz2yHY8UIykkj2RL8ZRQ0w/tHoXJRx8Qpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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