SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '420d3a031149ee2744bf17396ccb190ebc75ca235b6576c2140a053bf723e2a0' 
  AND token = 'bGD4aHq+WnkBI9LhMx4hkvFp4VqUVAx83snjz3JqHoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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