SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29ea64b0f76e551d4200261c5badb20712b98543af9cfef94f111c9ff511091a' 
  AND token = 'l+3cXIiSuLk9VxG3oH3fqW9P9ZOYehwGLYD3lTJ4kcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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