SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '861748eb19a515ff7ed44322d11c1d1ab822024b73d6bb04ecff16b5874daf48' 
  AND token = 'YdVeE4eXw+8AOJG4SsiSXfyWNKQzWxzmvQeBya5nS/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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