SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5957fd85295e91e4eff3cd0407f06a236b1c00e74bbcaca98b91e345e4840a5f' 
  AND token = 'KRUvAjMmw0+w+Jq0mLzYXrWpTVonztxTyxd36Z8J3Vs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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