SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e6b4b7d2351c97d67797be963d1be5be209d6b9a1d7da8e8db7d3b7f39c0475' 
  AND token = 'LOYQ0q3Frv9qKmDW5QbIiBvMhq1V9Sfw1BKHWDYAm98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00101

JSON explain

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