SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6578a7f0bb620ae81cfcd728a199efa8e01a3a54b98e76f5cafdad4d361caf6' 
  AND token = '6P1vHaJ/0w6jIERqonJ/mbAUDXZEO8Br+xQkhMS4zzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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