SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9348f260dbfcc5535003cdb4e2944f068d709b8a3ca5ea50f0329f7fda3fe57a' 
  AND token = 't223U2XPeX5IIq8F6kMsPJfGIn7+cZWY4Qk+PXksGyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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