SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a1ee687438d42df27239faa0203bf983f6494f8a9b449212d84d9182382c086' 
  AND token = 'ifPQhxS9Yky8pUbIkqSlcvWzR0GWSLcJG87cCJSyI0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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