SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd5157efdad4a4dd302296b9810d6045b392fae53ea8659909187bd769a046710' 
  AND token = 'fEC+aDFsvDj/ci4pUFlxvmHh5EbIG7tLEyaC3h4FE/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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