SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b08166e6056acd7b4472954cbc814f177ee283d51fba63ec1c9ea79c0cf964fb' 
  AND token = 'sXKL1YIJmPBZQh0I1kOmcE0igzP9xsxQCFE5OsyHqMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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