SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '930b69a88d20b826700879d96f3d670d07e95a2bdc65394a75779775d40d9927' 
  AND token = '2Dz/FWNf70io32lYyHplm1rkioj3PE3BZpCwhrCCqNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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