SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7daa5c95a6918679b970459148646c9b3cc2d78dcff017766161c708a63a7261' 
  AND token = 'MN1r4uAhpvtDmStV5Ap6OKC0cQFjTZbMJOp+O4uJZRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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