SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38e0b94766c50881abfb912f25fac5f7e4d6e092f550d2415971e26ac2b6411d' 
  AND token = 'vgkLq2rKYLBEDZpwPLRF4Wn8GKdoo/AFvxKh1SNGaO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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