SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be6026336aeb0a9c9ad3046f8baeb490549e5a65333330eae2ed3a27f2b29411' 
  AND token = 'bv59qo73xCp9Zt6dpAdd7RlclehJyb7Nh/mMUeaHCGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}