SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e95bf9ce2cdb57939dc43705f2a4cfde6a09d37945883bc466be14fe08908665' 
  AND token = 'R0YvQSTF5ySsAwbyt/PwnWWVG8IZ/gt+hR+ZLCzCoSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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