SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e81b56051d0399634f095bfa7341ae5d1eb39021628d3ec651d215e62933111' 
  AND token = 'repV914MYyjVZIN4TucJi25uwqF6+Z7aTnVGJPrqkvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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