SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bf075d2bc1283d44a83d2e215c2e77b440754404f09a8bc5b0638b0848be15e' 
  AND token = 'pybbfXcV8vXsIkvV/B9T+/ARJJNI2eMDMJcdj6DIpYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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