SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3d774d9a45554ceb274d1c8fab2602676bdecb7fe987faacb8794051c788aff' 
  AND token = 'vJf/+d/LjQsTP0mRK1lK9niKBy/KY8TcEK3My/gB/Ig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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