SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c5422ae9569fdd39562fd8085f1b38265a9cacfb681cc09e803178d17ed2ea' 
  AND token = 'C2ZcxTu5E3VK7LGdwjw8fQYEIPtzDJQ2zHvrQX3wJLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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