SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1b8e37e0583f6c373585405882abcfb4eadbc41177648a1e60c2223ad1f686' 
  AND token = 'r9PddKbyqrZ+7N/AUO7gtXXJ9hcnR6WjLyZRdYcjpGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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