SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef948ac271bb76016074db98302c83e41916a97ca34dbf07cfad5229ac3b77ad' 
  AND token = 'KQqIDeXQfZWZZS5YuTZmjh/kotF0S4xEZavf2yYOkKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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