SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3d6014891b0d706bdfc0edd828251db0594c0c7b9d691144fa1b64fbaf86828' 
  AND token = 'ytq3BbdK/tPbvHOJop+p95YU7FWlrzzOYvr7cFwuzMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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