SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8b7de98440e1032bf37e17b815cd34096b2448aca692240cbf150d62f6592b' 
  AND token = 'w+JGWzlqf/EbxCoLAh77qe11gTM/vadg2KMU/vlQUm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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