SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3abc1a8362fad18f202a4c15a3087ca36fe443b2ae31c16aaaab212c38ae3bf' 
  AND token = 'ql2gwahASqOPBtMermsp09BBsYjb1qCfKfJY3r3uvD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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