SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '608bc1471f4c45f772cd4953e0baa779631766f26089a5081815c64bd9213b82' 
  AND token = '2H80oMKVQv9VK/aNMv5foK6D/wX1+rPIWs7NEA2f3Gk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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