SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adff9083c489240c2c599ba56bd69cd095b06f0cd4e5a1f16034e89376d50577' 
  AND token = 'lh9MSHExwCKuekhgntfgItrrR47WUigsVAwjIWAcUAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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