SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16a38fff29f8b10633bcedd7eda05a27213748207ad9e9807d16f069a12799da' 
  AND token = '32kqJApQP3sXV4zAuz852rBjH0gbFsfXD/1WBGWLDAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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