SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2f1296e6c17b1769160a04db7e5b5639b9d1d02ee4d888a11ca433b2e06a781' 
  AND token = 'IJ8CfmdCDGs+XNMYRZZWnxpNluNWI9R6e3HZpQ5/vKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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