SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d2612aa81ad0d287d066692e29aec185952058f012568eb7411906148f8f596' 
  AND token = 'SJM5nsQpi/M6ikxYJXoS+NtiSeWakCZ9SrkqFPvL/AQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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