SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8564a5d71163a69ff2ef29a4e8c0e89b38847afb76b2b64bb2706e22c0ec9f36' 
  AND token = 'ebhXDtZrxOgFWS3eeRGoHyAk5hteieuyIcuew4BvZMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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