SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e5a75b139f03dac2eaee7545814b7477e3db12c534607b9693698fd136a737e' 
  AND token = 'Jaqf0Ech3W9ANa2ww7aWpvy2MdsOgYTvenbQUqXv5SQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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