SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '624f650a2c48633baa8abf20fb4e344bc76da219c4ae2b68c6dfa1a47bdf255f' 
  AND token = '2SM+meR6K3P2m8cBoyBSIYM+ZPn6G1lC8l+HtEVljW8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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