SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '317f95fff605032da7e38e0e323ff0d857445369e9a6f64be3fa6981eb866cd2' 
  AND token = 'NUps+vrDKrzwrzscFwjgJdaUMCawwLa1DoDr8jz9oSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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