SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46d2cf5e531053ef4359729a06bece9ca54d7f0edff5a543e5509ef17a63bf85' 
  AND token = 'tO3mhDg7rFy+quV2LPnhozrTl+W9HiCNrFAdCdEl/Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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