SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b158e37af0fd9d21e8f1402c73d5067b946626cfc5b9243a85fdce95c3f190a2' 
  AND token = 'BsHoRGmwXYUIc65HyID/OkqDySGvPDaNvymf/TZUg4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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