SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd40f531d0c4e7c28cff3d7be07c940bb900e2fed43efa6363038d564a45ba248' 
  AND token = 'yYfq91zcOrrnykVFDtPjHL1psNNr1u4HLfXYbSjJU7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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