SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fec1fd2e28bc93b696a626e643a21def7f581c20c4b125b6bbfd940e650fa8a' 
  AND token = 'WqlOgI9HTTbzuWoLHG8/SCLM7yJ5Ncxmc/Pn4D/NF5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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