SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85881a8604d891cb055c474e3b42095ae84ae3e2f48ef616c90ded5cd1cd38f5' 
  AND token = 'l9yBIDHU3MoFDE7MuoxiOm/lSSuionWV14mQRUKGGXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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