SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d1b6757abd1561c2bf54669a64a70522e0e0a66d46f1117c876f2db4d7b2c3a' 
  AND token = '2MukUY0tL6i+z/F59EKforpmrkNB3CixqPBuUT+57tY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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