SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c75879522bd65863c44d28d242a3da3a4fb761a6fc152568eb91453cd801039' 
  AND token = 'YyZPuSK6Eh3YmzSLG/OlzhM5FtpCzzsufwnMup5C24w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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