SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c06a6f887933b477e8320346abb3c2b548dafdcef2f9cacc02e0f197ea2f953' 
  AND token = '6VP9HwYas7NxTKKpK1eln4oAghIkHnBBsRdPD+Rjovg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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