SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9df52945211bb63fef8994e2d4df183beb506c088a0780361a658bb21dfa0de9' 
  AND token = 'zct8NzNmwLk1+aYRU2uNB9xpFkJB5k5VHzSVFKzPzrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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