SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f629a41118f5089e69cfa91751b5e452b7dbee78ec1b98d57397dee569ce139' 
  AND token = 'IPgoB2aNHeIpOuUn45mML4v+EzhlVYFnmezTSjTeLiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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