SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d8e64a2e126573395a1345e4ffd6e6b5f9f775901e100b3c52624669ce5cdd8' 
  AND token = 'ImL1xg2u4YKquY/HoSZ5zK+OPs60cE8hFgPKGDo/zGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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