SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76e0d6ef80fec0e90f8a45633c7e30879899857be97662609a7fcf6fdf39ccb8' 
  AND token = 'N1EJLrLI0GCtrGJCPUevsVvhJRvHuHUxBeyhkFvKzwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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