SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b82143fe74eec463ff4812d3358211e0edbf4f78bff9114d8b7083a1645e05d' 
  AND token = 'Gr6N8KMFs2iswImBvTHuvBDn4vqjCWqV5NTGMy0PTKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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