SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '713443835e510df7d2a81935abcde50f278b56c4290785c68bf131083253863c' 
  AND token = 'GTw/pEG8K8H91TThh0zG41Lyp7+lNPx8hceVNQ1OXBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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