SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b3a964f880f20bd2673fc979eb018023a038bce0ade530bf89fa5c9371a1286' 
  AND token = 'afeZ4QOJah1Bfhey1mqY/E6zqxs5OF4ABlG3lodmv8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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