SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3e8febb5169806e07b4ccf74e357098b8454b7db993a9d9dc95604f4a0aa6d4' 
  AND token = 'TlGxCFG2YXxRHXtrIQqJkCzfnlzfzc24Pj5fVfgu/mU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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