SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7512602be05b4a9aafb4b152aab036347c30c550c221539a321f14c85b149c81' 
  AND token = 'TUGu++OHWtVRoVxMFxk2eRy9M3Ktn8hpANzLFR8BKVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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