SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '212ee369cec635dc738ab9184b26c906a983166b3270259fb9d6fe20d456224d' 
  AND token = 'mDJx6WwZywV9sq6tZtnbGfYN/obJdbTwUXToZltZWmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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