SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b4f116a1df68b96fa8fbc64d6278bb7b05366b972a44c64269193a1c5915e6c' 
  AND token = 'OmOoUGITQXGXzyNtzABKvnnHPHmEc3fHDWLFQRYnjEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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