SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2020fc66d6fe8097712454647d4b872b48039b90c6268fc89c8b1a5544fcb41' 
  AND token = 'KQg3yaxzJ9uHvMZCKYhTgB0XihtQTJNwpBMX86Gqsrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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