SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e30b46e682db43fa023577a68a699e6980bedd5b0e3f39be92b747fde141a66a' 
  AND token = '0CArZ1mheTjKFKglytzPtcCZ0SgXVS31d1pYBewq1lQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}