SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b729132f910f3cacb8ce11aa589830117f5e402e5915e62b96b895b085eaa6aa' 
  AND token = 'tizya8eeBdfWv489ERRb69MnMpto6kqcDfSpEwNiIps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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