SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '435e751acc9deda3aa52a5527c94298fc455f002dc29100be2caeb30df9e4edd' 
  AND token = 'defkPrXruMzx8pTnUoNcibW9PR3ovUSaTh83FDJq7o0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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