SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ada794bd0a70152283c59eb9cb953c5a36327ec66ccb436cfb77d2bcc7925474' 
  AND token = '6ERBmwzQfc0BWih8JIFMbZLpUfawV9i0KSqzlQyr2vY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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