SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8c7e9149d9bc11ba1d0fbe029589d0481709f63a5905975e1e465946fcc210b' 
  AND token = 'OTNhLCmnXrEWZllYHLP42yQPiSYueTmJonI1Lta7V80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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