SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84b572f14d0e08a644445c7200786263809325b5b411be0a8ee48e911c5cc1b3' 
  AND token = 'MtjGyijjLt5/LP+Lx/+dt0hdfr+pQkqqI/TiWCSdAEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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