SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62c6a8431a039193867c191cdd21388520649b5a4cbad90fceb3819af4b5ada3' 
  AND token = 'sumE1NfFNoB2m41ZeT+JQzB/gpJmeAuwoEzpu9HsBgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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