SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad21696a9c15a3491f1cbc3ae653645e59704b84917a7ff5d2129d5c95221451' 
  AND token = 'fa9ERF9K5iTlnGKXdiquUSdmIuGvn8YsgZmEQUorAU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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