SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f65b3282895c8d521437f20c40a33f54cb65e25d18a8b8b9bf4995f9608db77' 
  AND token = 'a2L5OjY7XDcPJzzJ6GVZrkQm69kXvdlmMx9qNuMxhIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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