SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd803742faa2f9976d93c2bbdcca23a156d703875425fafaf6875f4caf1896080' 
  AND token = 'uwOSydQZ1+dVrv6/cwU/Hd1EqVtaCC3yDBcn+G3Whyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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