SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8439428a1109d236e06fffd9b092a5caec19869fef6fe3ba4c1badcf889e8de6' 
  AND token = 'MbL1pUGEWlt2paMlFhH7q3TDeXDsbDjbaNclmlIYHl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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