SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '892bebba91982fb62d0d8e87e3e6660c30e3305cd3bf35bd2bf6f3fef3ee3d34' 
  AND token = '4ZHQEd1kR1aJYljD6pLwnPOagaxw97QHH8MTnbV7kSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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