SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9496f12893ad3175b9652d3c8f272ca02849d574531145ba1ccb81f8482042de' 
  AND token = 'gUNVAsJuSIwY+pdLpEedGXSKzgBCQaaMQn021YTxqcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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