SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a60cbd592c3c0f410788a1e8aef1f6929afe29dfee196cffe00c9811bc8181c2' 
  AND token = '+b/SItOI89uGQMdJk//penrfrUNgiJtQ3wCwifyHp/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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