SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f61d1187431e0fb25e7ded751fc2f99814ca2b058feb4191424d57905cf6135' 
  AND token = 'WVEMAqDUCxaGGJWl5clrwF4cwdKANOOK5nLvpGcfpF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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