SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a9970d7832f010069df32f77695be395bdf5cd1a156c4a38675b3e5bae98bfe' 
  AND token = 'KDD5XZzMjxYLqr4DHdoFOUAhZIKy2QpaT2xkxZPmBxw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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