SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '749318a365af56d7d4dd5bb4223c9fb29284ffea3b7e325598e58714bf14956d' 
  AND token = 'rLZDvDRF+3Hz0xqhlzeC4NgJJPVHLSOyYcp33y0bY+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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