SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '633ae43ba155cf0662bcc7024278deca55c6b5eb98175abedfc28b0936f53fc8' 
  AND token = 'Zf8QnqIXZSdFPLrJNjQ9CLZJKvz0tDF0mBwPANAOVgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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