SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5972527a7d16affa1c498f49c0d37a74088ca661ea7b683cbd6688da1229b5f6' 
  AND token = '/nhS3xiFc93TawejRavGZKbQ8BVHC+FIahy3KHKJN+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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