SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff02a1dec4ba9838e3979c79f101111753881c4dff95e178964884aa0c5f68c7' 
  AND token = 'OsF/LnBZuXTYqhQgGjYjeLaV6PJEIYMDhtoRtNzhXA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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