SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6d2bde507170313552cf169f95b9a831eb5d866dc99f85c0abd4b996f62e28e' 
  AND token = 'P74PDNl/Be7R8EMqzoN/6K6bCj1ArJgHx7mB3vG9Mgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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