SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a028e9087083345455138c093e647209e01ec16a52693f4bb06742d0b3fd685' 
  AND token = 'Y+dAVkOAnVjiJfg3ZvHK4LgFlh6htaispz0UR3ix3as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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