SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d4863b990590b848d4072ff5cb308a376bf5be3024a7eae0e6bedc55e8a8c8d' 
  AND token = 'nEedO14qIsfI9th34LoCAuPDzeAZwjninrKsbxbwrK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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