SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d68203e3fddfdd074c7e4175ff998353b7a34067a9496139fa5764ad3abd61c' 
  AND token = 'Gwhokw2UlawEH9BZb+UZ6Nj1T3UyCkhuGoRsQr9SSAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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