SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da37721e7c4dd22e1bf2511184374f2f9259e187f00f9ea2e118321569fca1da' 
  AND token = 'wixUrmnuoe2zFzC+wHDgpuUw+NZP6ovBWhiZgnKW1Kg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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