SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dcd4eed5234ec57fbcfc81a3c8eea48340bc05a577524c570c39f5a53cf69ca' 
  AND token = 'KcSpwqzCMbSYZl6XzxSp2u/D3fC3Ds/np3iNhTAixw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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