SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5748d2bcb4bf99a2072f9fa8eedaa7840f31fb260518c4bdbed583e6e7034535' 
  AND token = 'emKwoqDClQnpaUu+V+UsaQH/6IVwr0wx2WcCTHRrKC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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