SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd31bf70d0bb8fc5937ba4e565d31c9aa624fb8dc5d6061e8176b51ff312167a' 
  AND token = 'uKdaVdVmyYRIKfvNN++0SR93LLALWKgRgzowyAlgboE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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