SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e79298ff3e9105a06cfb8e25c18dca18c8add6bc4f5fa8d475fd154e7199435' 
  AND token = '7TdIvaLpqpc2lTKwIoMMla55LpiKNRP6JF7VeYAgAJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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