SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '17f7fb0108311a65021117b909452589450269ec4f811b9834338752d48087c7' 
  AND token = 'C5Aj8D/cybL8krqSAiPRiEMt0k0t8K09E38tHZBwv78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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