SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28f8f5b485e05fd8ce501e43352ab9f568d34e25f5be5257b538d4bd6bb5fe4a' 
  AND token = 'd9+YT26xahioE0j7me6wkPgecWJ08kudx6Vt1nWM+AQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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