SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '471633f8697fac8488dcb35779d3724800650ca9f2a600b3e9516e75d86dabcc' 
  AND token = '+qYAB1TbWv8HgjrhMfo+vIhToSs34ypHSjZScRAhlDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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