SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f248f3f6eacc875cfe4efe08d5df46b9cce95808be13b46dac0ae13a90a60d' 
  AND token = 'JMstEuslm/tHioiNMN8KpmTYfO/EDzRbC3WIkV7CfXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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