SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef982a136182a9c47887edba33000259611b6067267b93f527f25c4c540f38f' 
  AND token = 'V6m6I97jhQZJ7qpsb/KFfxLuYoBk0+9iwISuL2LygO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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