SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab121b5a378d6012532a741e51054b90196684455e448e604bb40f7a8753074' 
  AND token = 'ZczxrI+8fo61lB6vjOCxV3DQdjvhW6AIfRyXPA6bbeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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