SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70e9633a98445eb2cd6972f2d0ad25d3b4a87a058c5749dfbb871639912d09c6' 
  AND token = 'GtojsfI5fOw0ycXAY/ivcQkQVOUYBHkdwJdOh+xWiTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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