SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9b9ead094d55a4758b69d5c902068bddddea7e451de858b7fb90cde3f10afbd' 
  AND token = 'V2Img/ymk+44fQWWj7KpFBkIURNP43Utcp7PNmH9Nzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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