SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bf003c2960db2e522d3f04769be23e0f68b8398fc08c30277500a3cf8574be9' 
  AND token = '2KNbjIZVpEkepHwU8Csp29w9ikx+vNw44lTUnESezos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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