SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b567241332057677d85a6ac87b66b3b522bc9c1338c12d87de11b059a131544' 
  AND token = 'AMu7rjMp1+HtWsgYfHJk52faL0lZU8snEDuNxJVpmBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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