SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de782606c97fffc3831e417bd0ac391701ab189d983559224725f27f0c01c45f' 
  AND token = 'QpC/n+aVt7I4epHAnVv8Mbl060IpuiJnix/Y/qWdFoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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