SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d8e33004c5d4bf99819cdbbccfcc44b611389a607d77d16e16543289b35f3ba' 
  AND token = 'MopoiPlHfErJzKMF7lhALO4zxGrjouLH4qbs9Zuerhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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