SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aac420ceee54b03e3097d845b5c5abf42352c406ed114e9a26ec29b1cb40ebe6' 
  AND token = 'Dk6nR0DWsDeEIe9U77nP46+QLlsPacNvlqkePzVg6XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}