SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '943e3843d1280ee27ec8225ef01eadd0e4a72ecb78246966fe9769692b04d327' 
  AND token = 'ACCdQkpWJaOM6Zh0vtgAVZzIdmeG762YYU7pnhpJwpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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