SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c08af058409e7f783f61917296d51de17e33b3e8b783e3d6f4d80c51632bc5b1' 
  AND token = 'SykKtfVOKNpNJII4u0bVu9Fv9jvgzDsHvHRdYaBFQgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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