SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '119e9c2456f3d94ad5229b61cb4609366db51aa0a6c49b436f7f253226fabf64' 
  AND token = 'waSvzAU//ymJquUU6N5M0AxeHXAnf7WG4fkLE8Ix5Nw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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