SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '87c4ebf4bcdf5bbf27f8b223e2ee538265d554773da22c50f16e06b912c825ec' 
  AND token = 'NZpVa/w3NQpWyLG1GdYRiSZwO59wgyrSfLPfp0/qGM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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