SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '611df1ef365e21de5fdfd852504c0cac250fc0a48ac0a83ee3c84310bd2a34f5' 
  AND token = '2LMqxUOvw8FexWbvBd8dnDarUn0HA6tyMjzazpOHTRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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