SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4aa6046e0d3f4a5d0feefe076ec733c82123433d741e1b900964792931dadc1' 
  AND token = 'pYECeMAqtYGy39mvw59iGeoTN8B/IczbFc/S+5s9ohE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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