SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45598ef93142dacb1a66055177c23819bf093d212d3e5f0f308c7365108a843' 
  AND token = 'IFf0FYM5ZV2UDxqepRXquj/io5jPv1e7WpGdXdYNlz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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