SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da5db5f63c6bacfb52224cd6dcb555e03b77b6b9c82967b2f40ff81338d4246' 
  AND token = 'zO8lVmxqGzEChWTHlzYKyHM7VGeATWLiKiGlj4agmu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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