SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '716ac7707024c10001c290bfd5d31a183fadc80e8ab1d81e5970618b416e8f0c' 
  AND token = 'gxOaMBJBeKxlVuIxGrMw8VqPhui9JfkPsDOEF9xoe0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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