SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1993d2674db39a3a696866b744e4a24f8d7fdd0fcd511dad5af53cccd572eb62' 
  AND token = 'mCqBZrk86lmJ+lO+L5UPJwBv1J3qoNZMfh7eUUv10p4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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