SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f418a4fe6a5ec4a2a0bf0d9a72cafc62947f1836ea32b6c296c6c01291929508' 
  AND token = 'kI15GdhdQE9EwPx715liMr3XOkmkDm0oxwBFXxii4Hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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