SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b72552013f58c2b028853e1d06ee631ce6b7ebd2a3c0fc9065c12372357e09cb' 
  AND token = 's2/4ybDKt6+FIZFIlvwGuK2R/w2Of2OJzfG/wqQVqgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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