SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7d3650fdc2713977e1e84793d74b6ed2a645ae3407b829b24a440f5281a74b2' 
  AND token = '5VwSbUSSpQMHwVdCWmgITeCzUN7zad2bjqZrU00F6FI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}