SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ecd254925850949285ee201d423df9be73ca1078005e1fc259d5e92f9105333' 
  AND token = 'PJSvVVC4GjqDnBIcSjjBmKEb/VKQqhjdJb3qVnQrEI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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