SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56b12286d4c03ec067a55fec66a00e0bba5dccbff13a4400ab61117f482619af' 
  AND token = 'M/4ug+lZVFQv6OPNZA9FLAKnOJNw2UbJm0GEKXY+6bU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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