SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4bf496fa2a2f2649d118b6eed67b1c56b49ccd8bf5157e0f6b2f6a3e838310c' 
  AND token = 'PRHjXVbUN4JEYSKk4CElxgEdw+SfYjDhSgM+oly3ZcE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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