SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '657a081580f84dd2a6e91dda0e450f584152184b9e2be9e038b399d7d6afbb82' 
  AND token = 'yyx1Trj8OkBXszulparIplBqot4msokL6dHn+CMTkdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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